2- Methylquinoxaline 1,4-dioxide

Elina and co-workers have extensively investigated the reactions of 2-methylquinoxaline 1,4-dioxide and 2,3 methylquinoxaline 1,4-dioxide with aldehydes. Under alkaline conditions formalin gives hydroxy-ethyl derivatives, and aryl aldehydes form styrylquinoxalines. As expected, 2,3-dimethylquinoxaline 1-oxide yields 3-methyl-2-styrylquin-oxaline l-oxide. ... [Pg.414]

Benzoxadiazole 1-oxide (473) gave 2-acetyl-3-methylquinoxaline 1,4-dioxide (472) (AC2CH2, NaOH, EtOH, 55°C, 90 min, then 20°C, 12 h 54% or AC2CH2 on Si02 gel, 20°C, 7 days 58%), 2-benzoyl-3-methylquinoxaline 1,4-dioxide (474) (BZCH2AC on 3A molecular sieve,... [Pg.63]

BzCH2C(=0)CH2Ph, neat EtjN, 20°C, 24 h 21%) ° 5,6-Difluoro-2,l,3-benzoxadiazole 1-oxide (476) gave 2-acetyl-6,7-difluoro-3-methylquinoxaline 1,4-dioxide (477) (AC2CH2, neat Et3N, 5°C, 1 h, then 20°C, 1 h 72% analogs likewise). ° = ... [Pg.64]

Benzoxadiazole 1-oxide (481) with 3-acetyltetrahydro-2-furanone (2-acetyl-butyrolactone 482) gave 2-(2-hydroxyethyl)-3-methylquinoxaline 1,4-diox-ide (483) (KOH, MeOH-HaO, 20°C, 24 h 50%) but with 2-acetylacetaldehyde dimethyl acetal (484), in the presence of morpholine as base, it gave 2-(2-morpholinovinyl)quinoxaline 1,4-dioxide (485) (PhH, reflux, water separation, 9 h 47%) ... [Pg.65]

Dichloro-2-methyl-3-phenylsulfonylquinoxaline 1,4-dioxide (55, R = S02Ph) gave 2-bromo-6,7-dichloro-3-methylquinoxaline 1,4-dioxide (55, R = Br) (48% HBr, 80°C, 30 min then 20°C, 12 h 31%) 2-methyl-3-phenylsulfonylquinoxaline 1,4-dioxide gave 2-chloro-3-methylquinoxaline 1,4-dioxide (35% HCl, 70°C, 15 min 87% several analogs likewise). ... [Pg.144]

Bromomethyl-6,7-dichloro-3-phenylthioquinoxaline 1,4-dioxide (245, Q = SPh, R = Br) gave 6,7-dichloro-2-(2-hydroxyethylamino)-3-(2-hydroxyethy-lamino)methylquinoxaline 1,4-dioxide (245, Q = R = NHCH2CH2OH) (H2NCH2CH2OH, CHCI3, 20°C, 4 days 62% note concomitant aminolysis... [Pg.177]

Acetoxymethyl-3-methylquinoxaline gave 2-acetoxymethyl-3-methylquinoxa-line 1,4-dioxide (244) (excess m-ClC6H4C03H, CHCI3, 20°C reflux, 16 h ... [Pg.228]

Acetyl-3-methylquinoxaline from its 1,4-dioxide (256) (TiCl3, MeOH, H2O, 20°C, 1 h 39% substrate, Et20,20°C, TiCUJ, then Zn dustj, slowly, 1 h ... [Pg.232]

Acetyl-3-methylquinoxaline from its 1,4-dioxide (262) [substrate, Nal, AcMe, 20°C then (F3CC0)20 slowly, extremely rapid reaction 86%] analogs... [Pg.234]

Methylquinoxaline 4-oxide (264) selectively from 2-methylquinoxaline 1,4-dioxide (265) (ascorbic acid, H2O, 90°C, 5 h 58% homologs likewise) the natural amino acids in foods can also reduce such quinoxaline N-... [Pg.234]

Azido-3-methylquinoxaline 1,4-dioxide (293) underwent thermolytic ring contraction with loss of N2 to give a separable mixture of 2-methyl-3//-benzimidazole-2-carbonitrile 1,3-dioxide (294) and its rearrangement product, 3-methyl-3//-2,l,4-benzoxadiazine-3-carbonitrile 4-oxide (295) (PhH, reflux, 10 min 46% and 41%, respectively) the latter product (295) was also obtained from the benzimidazole (294) (PhH, reflux, 30 min 76%) or from the quinoxaline (293) (PhMe, 90°C, 30 min 94%). ... [Pg.313]

Ethyl 3-methyl-2-quinoxalinecarboxylate 1-oxide Ethyl 3-methyl-2-quinoxalinecarboxylate 4-oxide 2-Ethyl-3-methylquinoxaline 1,4-dioxide... [Pg.407]

Methyl-2-quinoxalinamine 8-Methyl-6-quinoxalinamine 3-Methyl-2-quinoxalinamine 1,4-dioxide 3-Methyl-2-quinoxalinamine 4-oxide 2-Methylquinoxaline... [Pg.424]

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